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Extrusion Machines, Process & Requirement for Plant Set-up

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Pre-stressed, Precast concrete Hollow core Load Bearing slabs / Planks for Floors, roofs & walls

It is produced by simple hollow core concrete extrusion machine compared to hollow core slip-formers machine. This patented pushing technology extrudes or casts hollow core slab continuously on well-levelled, long & smooth concrete floor beds which is low on cement content (Zero slump).

It has high load bearing capacities and also has an excellent bond to steel wire strand.

It is dimensionally accurate while obtaining optimum density for higher fire rating with a good finish touch.

Our Extruder M/c consists of: -

  1. Drive unit coupled with extruding screws or moving tubes,
  2. Hopper for concrete mix &
  3. Compaction unit made of high frequency vibrators.

Our extruder's design is such that operation & maintenance cost is very low. Wear components of the m/c have extended life as they are lined or brazed with Carbide tips or hard steel rings on Moving Tubes. All types of Linear Sliding plates, Side forming Die plates, Start plates, Supporting plates etc.

Extruder is equipped with powerful high-frequency vibrators for prefect heavy-duty homogeneous compaction system that compacts the concrete into shape under combination of normal & powerful high frequency vibration and produces hollow core slabs with early strengths in which a man can stand immediately on just extruded slab.

Hollow core extruders are available in wide range for thickness & width of hollow core slab depending on load & span of precast element. This machine are capable of producing hollow core slabs of thickness from 120mm to 380mm with width from 600 / 900 / 1200mm with circular or non-circular core's.

The hollow core slabs are instantly fixed, compact & smooth because of the extruder which is equipped with powerful high-frequency vibrators.

The Extrusion Process / Production Cycle: -

There are 2 basic technologies to manufacture Pre-stressed Hollow core slab are Extrusion & Slip-forming.


  1. Extrusion.
    Extrusion is known for the high compaction capabilities and excellent structural capacity of the hollow core slab. The key to an optimum compaction on dry cast is the frequency of vibration since the absence of water makes it more difficult for the concrete particles to flow. Some of the Extruders manufactured today do not use the high frequency vibrators; instead they operate based on pressing extrusion screws, which usually requires more water to achieve the same level of compaction than the Hollow Core Extruders based on high frequency of vibration.
  2. Slip forming
    The second form of production is the Slip forming process. This is a relatively simple principle where concrete is flowing on to the product in two to three phases (layers) each phase is compacted typically by vibrators. The Slip-form system is used mainly for shallower hollow core cross-sections and various other cross sections like inverted T-beams.

Conventional layout consists of following Main Equipment: -


  1. Hollow core concrete slab extrusion machines,
  2. Concrete Batching Plant with Necessary supporting equipment & items as per Requirement.
  3. Stressing Equipment with Single Strand Jack & Anchor & Wedges for Steel Strands,
  4. Mini Dumpers for concrete feeding,
  5. Plastic & Woollen Blanket + Trolley for winding & unwinding for Curing Process,
  6. Cross cut circular saw cutting machine,
  7. Gantry Crane / Lifting devices / wheel Loader & Handling Equipment,
  8. Laboratory Testing Equipment for Quality Control,
  9. Other small accessories etc.

The basic work flow in these factories is as follows:

  • Preparing the casting beds by cleaning & oiling.
  • Pulling and attaching the pre-stressing wires or strands
  • Pre-stressing
  • Concrete filling into the extruder hopper by Mini Dumper
  • Extruding & Forming the slab around the reinforcement
  • Marking & Labelling for identifying the slabs
  • Making the openings etc
  • Covering for Fast Curing
  • De-tensioning of pre-stress steel wire strand
  • Cutting of the slabs to Required lengths
  • Lifting the slabs & moving it to stockyard stacks.
Sr. No. Model Size of Slab (mm) Power (kw) Weight / meter (kg) No. of Steel Strands, Steel Rope Ø, Span in Meter,
& Max. Load Carring Capacity kN/m2
1 HC LB
120-600		 Thickness - 120
Width - 600		 8.5 100
8 Nos. 5 mm 4.5 mtr 4.6 kN/m2
6 Nos. 7 mm 4.5 mtr 6.54 kN/m2
6 Nos. 7 mm 6 mtr 2.27 kN/m2
2 HC LB
150-600		 Thickness - 150
Width - 600		 10.5 125
5 Nos. 7 mm 4.5 mtr 8.27 kN/m2
7 Nos. 7 mm 6 mtr 4.94 kN/m2
5 Nos. 9.5 mm 6 mtr 5.23 kN/m2
3 HC LB
150-1200		 Thickness - 150
Width - 1200		 18.5 250
12 Nos. 7 mm 4.5 mtr 10.98 kN/m2
12 Nos. 7 mm 6 mtr 4.54 kN/m2
10 Nos. 9.5 mm 6 mtr 6.19 kN/m2
4 HC LB
180-1200		 Thickness - 180
Width - 1200		 18.5 270
10 Nos. 9.5 mm 6 mtr 9.72 kN/m2
8 Nos. 12.7 mm 6 mtr 12.83 kN/m2
10 Nos. 12.7 mm 7.5 mtr 8.72 kN/m2
5 HC LB
200-1200		 Thickness - 200
Width - 1200		 22 300
10 Nos. 9.5 mm 6 mtr 11.36 kN/m2
8 Nos. 12.7 mm 7.5 mtr 8.11 kN/m2
10 Nos. 12.7 mm 9 mtr 6.36 kN/m2
Sr. No. Model Size of Slab (mm) Power (kw) Weight / meter (kg) No. of Steel Strands, Steel Rope Ø, Span in Meter,
& Max. Load Carring Capacity kN/m2
6 HC LB
250-1200		 Thickness - 250
Width - 1200		 33 315
8 Nos. 12.7 mm 7.5 mtr 11.15 kN/m2
10 Nos. 12.7 mm 9 mtr 9.16 kN/m2
10 Nos. 12.7 mm 10.5 mtr 5.76 kN/m2
10 Nos. 12.7 mm 12 mtr 2.86 kN/m2
7 HC LB
300-1200		 Thickness - 300
Width - 1200		 40 380
12 Nos. 9.5 mm 7.5 mtr 11.59 kN/m2
10 Nos. 12.7 mm 9 mtr 8.63 kN/m2
10 Nos. 12.7 mm 10.5 mtr 6.60 kN/m2
12 Nos. 12.7 mm 12 mtr 5.60 kN/m2
8 HC LB
380-1200		 Thickness - 380
Width - 1200		 39.5 480
14 Nos. 9.5 mm 9 mtr 10.20 kN/m2
10 Nos. 12.7 mm 10.5 mtr 7.64 kN/m2
10 Nos. 12.7 mm 12 mtr 5.91 kN/m2
12 Nos. 12.7 mm 13.5 mtr 4.58 kN/m2

Precast Pre-stressed Concrete Extruded Hollow Core Load Bearing Slab for Floors & Roofs and Walls . Having Avg. speed of Extrusion of Slab is 1.3 to 1.5 Mtrs / Min. & for Sr. No. 8 is 0.8. to 1.0 Mtrs / Min)